This invention relates to vehicle turn signalling apparatus by which the direction of a turn is signalled by a corresponding flashing lamp.
Heretofore, such turn signalling apparatus has generally employed widely-spaced left-turn and right-turn signalling lamps at the rear of an automobile, truck or trailer and has been used at night in conjunction with steadily illuminated, similarly-spaced left and right tail lamps. Thus, for example, when the left-turn signalling lamp is flashed, the steadily illuminated right tail lamp provides a reference which enables the driver of a following vehicle one-hundred feet away to discern that the flashing lamp he observes is the left-turn signalling lamp.
In the case of motorcycles, left-turn and right-turn signalling lamps are conventionally mounted at the ends of a horizontal transverse bar nearly two feet apart; and a single tail lamp centrally located between the turn signalling lamps will, when turned on by a switch independent of the turn signal switch, provide a reference enabling a following driver to discern at a considerable distance which one of the two signalling lamps on the motorcycle is flashing when the motorcycle is signalling a turn.
Each prior art apparatus mentioned above requires the vehicle driver to switch on a tail lamp (or lamps) in an operation separate from his operation of the turn signal switch; and, unless the tail lamp (or lamps) is switched on, there will be no steadily illuminated reference position enabling a distant following driver to determine in the dark the relative position of the flashing signal lamp selected by operation of the turn signal switch.
The need for a steadily illuminated reference position to ascertain the position of flashing illumination, hence the need for respective switching operations independent of one another, has been circumvented heretofore at the rear of a motorcycle by arranging four lamps in a horizontal transverse bank of adjoining compartments behind a common red lens and operating a turn signal switch to energize the lamps in a repeating sequence from left to right for a right turn and from right to left for a left turn, as disclosed in U.S. Pat. No. 3,484,743 granted Dec. 16, 1969. A tail lamp (or lamps), however, is still required for safe vehicle operation after dark, albeit not to provide a reference position (or positions). Thus, the sequential flash technique adds more signal lamps to a vehicle turn signalling apparatus. It also significantly increases the complexity and cost of such apparatus.
As far as pedal-operated bicycles and mopeds are concerned, there has heretofore been provided a turn signalling apparatus consisting of a small unit about 5" across, installed at the back of the biker's seat and provided with respective lamps behind right and left arrows of clear red plastic. A battery-powered electrical circuit arrangement in the unit, under control of a finger-operated handle-bar switch, selectively illuminates either the lamp behind the right arrow or the lamp behind the left arrow or neither lamp. At a distance of about 20 feet or more, however, all one can see when the biker signals a turn is a steady red light spot. No arrow outline is discernible at this distance and hence the direction of the turn is undetectable by the driver of an approaching automobile and, indeed, the driver might well interpret the red light spot as a stop or braking signal and begin to pass the bicycle on the side towards which the biker is about to turn.
Another known turn signalling apparatus for pedal-operated bicycles or mopeds consists of a larger unit about 10" across for installation at the back of the biker's seat. This known unit is provided with three lamps, two independently-operated mutually-remote switches and a battery. One of the lamps is behind a large red plastic lens flanked on its right and left sides by respective ones of the other lamps, each being behind a smaller red plastic lens. One of the switches is mounted on the unit and is manually operable to turn the central lamp on and off for tail light purposes. The other switch is to be mounted on the handle-bar and is manually operable to selectively energize either side lamp alone for signalling a corresponding turn direction or to deenergize both lamps entirely. Each side lamp is a blinker bulb having a bi-metallic filament which takes from 5 to 10 seconds to heat up and become active. Thus, a biker could be well into a turn before the selectively energized side lamp begins to flash. And, if the biker has not independently switched the centrally-located tail light on, an observer at a distance behind the bicycle or moped may not be able to detect which side lamp is flashing.
The aforementioned known systems specifically designed for use on pedal-operated bicycles and mopeds are accordingly highly deficient in providing the signalling function they purport to provide. Such a deficiency is fast becoming an extremely serious matter in view of the rapidly accelerating use of bicycles to avoid the high cost of gasoline, diesel oil and other fuels for engine-driven vehicles.